Assigning specific elements of vector a different value

Hi

I am trying to assign values to elements from one vector based on the values of another vector:

      r = [1,3,4,5,3,3,4,5,6,4];
      Postdia = [12,20]

For vector r, I want to pull out the element when the sum of r reaches 12 (Postdia First value) - and name it SYNAPSE. Similarly I want to pull out the element in r when the sum of the values reaches 20 (Postdia second value) - call it SYNAPSE also. The other values should all be assigned NO SYNAPSE.

For this I have written this code but it isn't working.

              b= 0;
      b2 = 0;
      r = [1,3,4,5,3,3,4,5,6,4];
      Postdia = [12,20]
      r2 = r;
      k = 0

      for i = 1:length(r)
          b = r(i) + b;
          for j = 1:2
              b2 = find(b > Postdia(j));
                  r2(i) = r(b2);
                  if b2 == 1
                     r2(i) = {'SYNAPSE'};
                  else
                     r2(i) = {'NO SYNAPSE'};
                  end
          end
      end

Does anyone have any suggestions?

Cheers

[James Tursa]

What do you want for a result? A cell array the same size as r, but with either 'SYNAPSE' or 'NO SYNAPSE' for the elements depending on your criteria?

[Morgan Roberts]

Yes that exactly

Answer 1

[Star Strider]

See if this works for you:

r = [1,3,4,5,3,3,4,5,6,4];                              % Given Data
Postdia = [12,20];                                      % Given Data
r2 = repmat({'NO SYNAPSE'}, 1, numel(r));               % Create ‘r2’
csr = cumsum(r);                                        % Cumulative Sum
lm = bsxfun(@le, csr, Postdia');                        % Logic Matrix
[~,idx] = max(fliplr(lm),[],2);                         % Numerical Indices
r2(numel(r)-idx'+2) = {'SYNAPSE'};                      % Desired Output

r2 =

    1×10 cell array

    Columns 1 through 5

      {'NO SYNAPSE'}    {'NO SYNAPSE'}    {'NO SYNAPSE'}    {'SYNAPSE'}    {'NO SYNAPSE'}

    Columns 6 through 10

      {'NO SYNAPSE'}    {'SYNAPSE'}    {'NO SYNAPSE'}    {'NO SYNAPSE'}    {'NO SYNAPSE'}

Experiment to get the result you want.

[Patel jaykumar Dipakbhai]

dear star strider, what if i want to assign specific values to each elements of the coloumn vector (v1)and same thing i want to do for another coloumn vectors(v2)? the values i want to assign are different for both coluomn vectors.

now after assigning the values to the both coloumn vectors what should i do 'to add the values of the respective column vectors' when the element of standard column vector (v1) is equal to the element of the v2?